Heat exchanger

ABSTRACT

The heat exchanger is provided with: a plurality of first members including walls that have introduction holes on a first end side and discharge holes on a second end side, with spaces connecting the introduction holes and the discharge holes serving as first channels through which fluid flows; second members that communicate with the introduction holes at the first end side of the plurality of first members to introduce the first fluid to the first members; and third members that communicate with the discharge holes at the second end side of the plurality of first members to discharge the first fluid that has flowed through the first members. In at least one adjacent pair of the introduction holes, regions that overlap with opening regions of the upstream-side introduction holes exist in the walls including the downstream-side introduction holes, when viewed in a direction in which the first fluid flows.

TECHNICAL FIELD

The present invention relates to a heat exchanger.

BACKGROUND ART

Conventionally, heat exchangers have been used in heat exchange systemsfor cooling, heating, and the like. As an example of such a heatexchanger, there has been proposed a heat exchanger formed by aplurality of substrates that are laminated. Each of the substrates has aplurality of strips arranged substantially parallel side by side as wellas slits between the strips, and is provided with recesses that continuein a longitudinal direction on several surfaces of the strips. Thestrips of adjacent substrates are interconnected to define tubes, therecesses define tube internal channels, and the slits define tubeexternal channels. (Refer to Patent Document 1, for example.)

CITATION LIST Patent Literature

Patent Document 1: Japanese Unexamined Patent Application No.2005-300062A

SUMMARY OF INVENTION Technical Problem

In the heat exchangers of recent years, an even superior heat exchangeefficiency has been in demand. An object of the present invention istherefore to provide a heat exchanger having a superior heat exchangeefficiency.

Solution to Problem

A heat exchanger according to the present invention is formed from aceramic and performs heat exchange between a first fluid and a secondfluid. The heat exchanger is provided with a plurality of first membersincluding walls that have introduction holes on a first end side anddischarge holes on a second end side, with spaces connecting theintroduction holes and the discharge holes serving as first channelsthrough which the first fluid flows; second members that communicatewith the introduction holes at the first end side of the plurality offirst members to introduce the first fluid to the first members; andthird members that communicate with the discharge holes at the secondend side of the plurality of first members to discharge the first fluidthat has flowed through the first members. In such a heat exchanger,spaces between the plurality of first members serve as second channelsthrough which the second fluid flows. Further, in at least one adjacentpair of the introduction holes, regions that overlap with openingregions of upstream-side introduction holes exist in the walls includingdownstream-side introduction holes, when viewed in a direction in whichthe first fluid flows.

A heat exchanger according to the present invention is formed from aceramic and performs heat exchange between a first fluid and a secondfluid. The heat exchanger is provided with a plurality of first membersincluding walls that have introduction holes on a first end side anddischarge holes on a second end side, with spaces connecting theintroduction holes and the discharge holes serving as first channelsthrough which the first fluid flows; second members that communicatewith the introduction holes at the first end side of the plurality offirst members to introduce the first fluid to the first members; andthird members that communicate with the discharge holes at the secondend side of the plurality of first members to discharge the first fluidthat has flowed through the first members. In such a heat exchanger,spaces between the plurality of first members serve as second channelsthrough which the second fluid flows. Further, in at least one adjacentpair of the discharge holes, regions that overlap with opening regionsof upstream-side discharge holes exist in the walls includingdownstream-side discharge holes, when viewed in a direction in which thefirst fluid flows.

Advantageous Effects of Invention

The heat exchanger according to the present invention has a superiorheat exchange efficiency.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating an example of a heat exchangeraccording to a present embodiment.

FIG. 2 is a cross-sectional view illustrating an example of the heatexchanger according to the present embodiment.

FIG. 3 is a perspective view illustrating an example of a first memberthat constitutes the heat exchanger according to the present embodiment.

FIG. 4 is a perspective view illustrating an example of a second memberand a third member that constitute the heat exchanger according to thepresent embodiment.

FIG. 5 is a partial cross-sectional view illustrating an example of theheat exchanger according to the present embodiment.

FIG. 6 is an enlarged partial cross-sectional view illustrating anexample of the second member side of the heat exchanger according to thepresent embodiment.

FIG. 7 is an enlarged partial cross-sectional view illustrating anotherexample of the second member side of the heat exchanger according to thepresent embodiment.

A heat exchanger according to the present embodiment will be describedhereinafter using the drawings. Note that, in the followingdescriptions, identical members in the drawings will be denoted usingthe same symbols.

FIG. 1 is a perspective view and FIG. 2 is a cross-sectional viewillustrating an example of a heat exchanger according to the presentembodiment. Further, FIG. 3 is a perspective view illustrating anexample of a first member constituting the heat exchanger according tothe present embodiment, and FIG. 4 is a perspective view illustrating anexample of a second member and a third member that constitute the heatexchanger according to the present embodiment. Further, FIG. 5 is apartial cross-sectional view of the heat exchanger according to thepresent embodiment, and FIGS. 6 and 7 are enlarged partialcross-sectional views of the second member side of the heat exchangeraccording to the present embodiment.

First, the configuration of the heat exchanger according to the presentembodiment will be described using FIGS. 1 and 2. A heat exchanger 1 ofthe example illustrated in FIG. 1 includes a plurality of first members2. Each of the first members 2 includes walls provided with introductionholes 5 on a first end side and discharge holes 6 on a second end side.Spaces connecting the introduction holes 5 and the discharge holes 6serve as first channels 8 through which a first fluid flows. The heatexchanger 1 further includes second members 3 that communicate with theintroduction holes 5 at the first end side of the plurality of firstmembers 2 to introduce the first fluid to the first members 2. The heatexchanger 1 further includes third members 4 that communicate with thedischarge holes 6 at the second end side of the plurality of firstmembers 2 to discharge the first fluid that has flowed through the firstmembers 2. Further, spaces between the plurality of first members 2serve as second channels 10 through which a second fluid flows. Notethat the “first end side” here can also be expressed as an upstream sideof the first fluid, and the “second end side” can also be expressed as adownstream side of the first fluid.

While the heat exchanger 1 that includes three first members 2 isillustrated in FIGS. 1 and 2 as an example, the heat exchanger 1 is notlimited thereto and may include two or more first members 2. Further, afluid, a vapor, or the like may be used as the first fluid and thesecond fluid, in accordance with the objective. For example, the firstfluid may be a fluid such as water, and the second fluid may be a vaporsuch as gas.

The first members 2, the second members 3, and the third members 4 thatconstitute the heat exchanger 1 according to the present embodiment areformed from a ceramic. With these members thus formed from a ceramic,the heat exchanger 1 has superior thermal resistance and corrosionresistance. The types of ceramics used can be selected as appropriate inaccordance with the characteristics of the fluid. Examples include anoxide ceramic, such as an alumina ceramic or a cordierite ceramic, and anon-oxide ceramic, such as a silicon nitride ceramic, an aluminumnitride ceramic, or a silicon carbide ceramic.

When these members are formed from a silicon carbide ceramic having asilicon carbide content exceeding 50 mass % with respect to allcomponents that constitute the ceramic, the heat exchange efficiency ofthe heat exchanger 1 can be increased due to a high thermalconductivity. Further, when these members are formed from an aluminaceramic having an alumina content exceeding 50 mass % with respect toall components that constitute the ceramic, the raw material costdecreases and machineability increases, thus the heat exchanger 1 can bemanufactured at a cost lower than that when other materials are used.

FIGS. 1 and 2 illustrate an example in which the heat exchanger 1includes a flange portion 16 at the lowest level. The flange portion 16includes an introduction portion 11 and a discharge portion 12 for thefirst fluid. The path of the first fluid in this example will now bedescribed. First, the first fluid enters the heat exchanger 1 from theintroduction portion 11 of the flange portion 16, flows through anintroduction channel 7, passes through the introduction holes 5 and thefirst channels 8 of the first members 2, flows through the dischargeholes 6, and is then discharged from the discharge portion 12 via adischarge channel 9.

By satisfying such a configuration, the heat exchanger 1 of the presentembodiment can perform heat exchange efficiently with the second fluidthat flows through the second channel 10 while the first fluid flowsthrough the first channel 8, in particular.

Further, when a channel that connects the introduction portion 11 andthe discharge portion 12 is provided in the flange portion 16, heatexchange can be performed in the flange portion 16 as well. Thus, theheat exchange efficiency of the heat exchanger 1 can be improved. Notethat the flange portion 16 is not mandatory in a configuration of theheat exchanger 1. The opening of the second member 3 positioned at thelowest level in FIGS. 1 and 2 may serve as the introduction port of thefirst fluid, and the opening of the third member 4 positioned at thelowest level may serve as the discharge port of the first fluid.

Further, in the heat exchanger 1, the first fluid and the second fluidcan be disposed so as to form a cross flow, or disposed so as to flow inthe same direction.

Further, while not illustrated in FIGS. 1 and 2, a partition portioncapable of branching the first fluid may be provided in the first member2. When the partition portion is thus provided, a contact surface areawith the first fluid is increased. Thus, the heat exchange efficiencycan be improved.

Next, each member that constitutes the heat exchanger according to thepresent embodiment will be described using FIGS. 3 and 4. First, thefirst member 2 includes the introduction hole 5 that communicates withthe second member 3, and the discharge hole 6 that communicates with thethird member 4, as illustrated in FIG. 3. Note that while FIG. 3illustrates an example in which the introduction hole 5 and thedischarge hole 6 are provided in mutually corresponding positions of anupper wall and a lower wall, forming through-holes, the first member 2of this configuration corresponds to a first member 2 b and a firstmember 2 c in FIGS. 1 and 2. Further, the first member 2 a disposed onthe highest level does not require the first fluid to flow furtherupward on the upstream side, and the first fluid never flows from aboveon the downstream side. Thus, the introduction hole 5 and the dischargehole 6 are included only on the lower wall of the walls constituting thefirst member 2 a.

Next, the second member 3 and the third member 4 are, for example,cylindrical members, as illustrated in FIG. 4. Note that a cross sectionof each of the second members 3 and the third members 4 orthogonal tothe direction in which the first fluid flows is not limited to acircular shape. As long as the first fluid can flow through the interiorand the height allows provision of the second channel 10, the crosssection may be an elliptical shape, a polygonal shape such as atriangular shape or a quadrilateral shape, or the like.

Then, in addition to the configuration described above, in the heatexchanger 1 of the present embodiment, in at least one adjacent pair ofthe introduction holes 5, regions that overlap with opening regions ofthe upstream-side introduction holes exist in the walls including thedownstream-side introduction holes, when viewed in the direction inwhich the first fluid flows. With satisfaction of such a configuration,when the first fluid flows through the introduction channel 7, the firstfluid collides with the regions that overlap with the opening regions ofthe upstream-side introduction holes in the walls including thedownstream-side introduction holes, causing change in the flow of thefirst fluid and, as a result, turbulence occurs. Then, the number ofopportunities for contact between the first fluid and an inner face(hereinafter referred to as “turbulence region”) of the channel thatcomes into contact with the generated turbulence increases. As a result,the heat exchanger 1 of the present embodiment has a superior heatexchange efficiency.

Here, the one adjacent pair of the introduction holes 5, according tothe heat exchanger 1 illustrated in FIG. 2, are an introduction hole 5 aand an introduction hole 5 b, the introduction hole 5 b and anintroduction hole 5 c, the introduction hole 5 c and an introductionhole 5 d, or the introduction hole 5 d and an introduction hole 5 e, andare thus two of the introduction holes 5 adjacently positioned in thedirection in which the first fluid flows.

Further, of the one adjacent pair of the introduction holes 5, theupstream-side introduction hole is the introduction hole 5 positionedupstream in the direction in which the first fluid flows, and thedownstream-side introduction hole is the introduction hole 5 positioneddownstream in the direction in which the first fluid flows. For example,for the combination of the introduction hole 5 b and the introductionhole 5 c, the introduction hole 5 b is the downstream-side introductionhole, and the introduction hole 5 c is the upstream-side introductionhole. Further, for the combination of the introduction hole 5 c and theintroduction hole 5 d, the introduction hole 5 c is the downstream-sideintroduction hole, and the introduction hole 5 d is the upstream-sideintroduction hole. Thus, the same introduction hole 5 may be anupstream-side introduction hole as well as a downstream-sideintroduction hole, depending on the combination.

Examples in which the one adjacent pair of the introduction holes 5satisfy the configuration described above include when the adjacent pairof the introduction holes 5 have the same opening shape and the openingregion of the upstream-side introduction hole is larger than the openingregion of the downstream-side introduction hole, and when the openingshapes of the adjacent pair of the introduction holes 5 are different.From the viewpoint of not delaying the flow rate of the fluid more thannecessary, however, a case where the adjacent pair of the introductionholes 5 have the same opening shape, but the centers of the pair of theintroduction holes 5 are shifted in a direction that intersects thedirection of flow when viewed in the direction in which the first fluidflows is preferred. Note that the opening shape of the introduction hole5 is not limited to a circular shape as illustrated in FIG. 3, and maybe an elliptical shape, a polygonal shape such as a triangular shape ora quadrilateral shape, or the like.

Next, a configuration in which, in the adjacent pair of the introductionholes 5, a region that overlaps with the opening region of theupstream-side introduction hole exists in the wall including thedownstream-side introduction hole, when viewed in the direction in whichthe first fluid flows, will be described using FIG. 5. Note that whileFIG. 5 illustrates an example in which the first member 2 b includesthree walls, the number of walls that constitute the first member 2 b isnot limited thereto, and may be three or greater.

As illustrated in FIG. 5, when the adjacent pair of the introductionholes 5 are the introduction hole 5 b and the introduction hole 5 c, theintroduction hole 5 b is the downstream-side introduction hole and theintroduction hole 5 c is the upstream-side introduction hole. Then, “inthe adjacent pair of the introduction holes 5, a region that overlapswith the opening region of the upstream-side introduction hole exists inthe wall including the downstream-side introduction hole, when viewed inthe direction in which the first fluid flows” refers to when the openingregion of the introduction hole 5 c (which is the upstream-sideintroduction hole) is moved in parallel in the direction in which thefirst fluid flows to a wall 13 b that includes the downstream-sideintroduction hole, and when a section that overlaps with the openingregion of the upstream-side introduction hole exists in the wall 13 b.In other words, according to the above-described configuration, when theopening region of the introduction hole 5 c is moved in parallel towardthe introduction hole 5 b in the direction in which the first fluidflows, a section in which there is no overlap with the opening region ofthe introduction hole 5 b exists.

According to the example illustrated in FIG. 5, a portion of the firstfluid that has passed through a second member 3 b and the introductionhole 5 b, when viewed in the direction in which the first fluid flows,collides with the wall 13 b where the region that overlaps with theopening region of the introduction hole 5 c exists, forming turbulenceregions on the inner face of a second member 3 a as well as on the innerface of the first member 2 b, which are adjacent to the section wherethe colliding occurred. Then, in such a turbulence region, the number ofopportunities for contact with the first fluid increases, therebyimproving the heat exchange efficiency of the heat exchanger 1.

Note that while the above has been described using FIG. 5 and thusdescribes the introduction holes 5 of the first member 2 b, the sameeffect as described above can be achieved with the other combinations aswell as long as, in the adjacent pair of the introduction holes 5, aregion that overlaps with the opening region of the upstream-sideintroduction hole exists in the wall that includes the downstream-sideintroduction hole, when viewed in the direction in which the first fluidflows. Further, from the viewpoint of expanding the turbulence regions,preferably the overlapping region described above has a surface areaequivalent to at least 10% the surface area of the opening region of theupstream-side introduction hole.

Then, while a description has been given using the adjacent pair of theintroduction holes 5, the same effect as described above can be achievedwith the adjacent pair of the discharge holes 6 as well as long as, inat least one adjacent pair of the discharge holes 6, a region thatoverlaps with the opening region of the upstream-side discharge holeexists in the wall that includes the downstream-side discharge hole,when viewed in the direction in which the first fluid flows.

Further, in the heat exchanger 1 of the present embodiment, preferablythe at least one of the plurality of first members 2 includes achamfered area on a center section thereof, on an edge of theintroduction hole 5 positioned on the downstream side of the firstfluid, the edge being on an interior side of the first member 2.

The above-described configuration will now be described using FIG. 6. InFIG. 6, the first fluid flows from the lower introduction hole 5 c intothe first member 2 b, and branches and flows to the first channel 8extending from a first end side to a second end side, and to the upperintroduction hole 5 b. At this time, a chamfered portion 14 is providedto the center section of the first member 2 b (the right side in FIG.6), on the edge of the introduction hole 5 b of the wall 13 b thatconstitutes the first member 2 b, and thus the first fluid can besmoothly branched. Note that the chamfered portion 14 serving as achamfered area is a section in which a corner portion serving as theedge is cut to form a plane.

Thus, because the first fluid can be smoothly branched by providing thechamfered portion 14 to the center section of the first member 2 b, onthe edge of the introduction hole 5 b positioned on the downstream sideof the first fluid, the edge being on the interior side of the firstmember 2 b, a configuration in which turbulence occurs further on theupstream side of the first fluid than the chamfered portion 14 ispreferred. With such a configuration, the first fluid in which aturbulence has occurred is smoothly branched and the turbulence regionis expanded, and thus, the heat exchange efficiency can be furtherimproved.

Further, while not illustrated, the same can be said for the dischargechannel 9 as well. Thus, at least one of the plurality of first members2 includes a chamfered area on the center section thereof, on the edgeof the discharge hole 6 positioned on the downstream side of the firstfluid, the edge being on the interior side of the first member 2. Thus,the first fluid that has flowed through the first channel 8 and thefirst fluid that has flowed from the upper discharge hole 6 can besmoothly merged.

Further, in the heat exchanger 1 of the present embodiment, preferablyat the least one of the plurality of first members 2 includes aprotruding area at a position on the center section thereof, in an areaaround the edge of the introduction hole 5 positioned on the downstreamside of the first fluid, the edge being on an interior side of the firstmember 2. In the following, this protruding area is described as aprotruding portion 15.

The above-described configuration will now be described using FIG. 7. InFIG. 7, the first fluid flows from the lower introduction hole 5 c intothe first member 2 b, and branches and flows to the first channel 8extending from the first end side to the second end side, and to theupper introduction hole 5 b. At this time, because the protrudingportion 15 is provided to a position on the center section of the firstmember 2 b, in an area around the edge of the introduction hole 5 b ofthe wall 13 b that constitutes the first member 2 b, turbulence can begenerated even when the first fluid branches to the first channel 8, andthus, the heat exchange efficiency can be further improved. Here, giventhe inner face of the wall 13 b that constitutes the first member 2 b,excluding the area around the edge of the introduction hole 5 b, as areference plane, the protruding portion 15 is an area of this wall 13 bthat protrudes at least 1 μm on the first channel 8 side of thisreference plane.

Further, while not illustrated, when the at least one of the pluralityof first members 2 includes the protruding portion 15 at a position onthe center section thereof, in an area around the edge of theintroduction hole 5 positioned on the downstream side of the firstfluid, the edge being on the interior side of the first member 2,turbulence occurs from a merge with a main flow that flows through thefirst channel 8 and a merge with the first fluid that has flowed fromthe upper discharge hole 6 when the first fluid that has flowed throughthe first channel 8 passes over the protruding portion 15, therebyimproving the heat exchange efficiency.

Further, in the heat exchanger 1 of the present embodiment, preferablythe inner face of the introduction hole 5 adjacent to the second member3 on the downstream side of first fluid has an arithmetic mean roughnessRa2 that is greater than an arithmetic mean roughness Ra1 of the innerface of the second member 3.

A description is given below, using FIG. 5. In the configurationillustrated in FIG. 5, when the arithmetic mean roughness Ra2 of theinner face of the introduction hole 5 c is greater than the arithmeticmean roughness Ra1 of the inner face of the second member 3 b,turbulence occurs when the first fluid flows from the interior of thesecond member 3 b into the introduction hole 5 c, and thus, the heatexchange efficiency can be improved. In particular, the introductionhole 5 c is preferably included in the turbulence region that occurs dueto the existence of the region that overlaps with the opening region ofthe upstream-side introduction hole in the wall that includes thedownstream-side introduction hole.

Further, when an arithmetic mean roughness Ra4 on the inner face of thedischarge hole 6 on the downstream side of the first fluid adjacent tothe third member 4 is greater than an arithmetic mean roughness Ra3 ofthe inner face of the third member 4 in the discharge channel 9 as well,turbulence occurs when the first fluid flows from the interior of thethird member 4 into the discharge hole 6, and thus, the heat exchangeefficiency can be improved.

Here, the arithmetic mean roughness values Ra1 to R4 described above maybe found by measurement using a contact-type surface roughness gauge inaccordance with JIS B 0601 (2013). Examples of measurement conditionsinclude, for example, a measurement length of 2.5 mm, a cutoff value of0.8 mm, and a stylus scanning speed set to 0.3 mm/sec. In the followingdescriptions, items related to the discharge channel 9 will be describedin parenthesis. Then, of the inner face of the second member 3 (thirdmember 4) and the inner face of the introduction hole 5 (discharge hole6), a section near adjacent positions may be defined as a measurementlocation, and the arithmetic mean roughness values Ra1 (Ra3) and Ra2(Ra4) may be found by measuring at least three locations each in adirection along the direction in which the first fluid flows, andcalculating the average value thereof

Further, a ratio Ra2/Ra1 (Ra4/Ra3) of the arithmetic mean roughness Ra1(Ra3) to the arithmetic mean roughness Ra2 (Ra4) is preferably from 3 to30, both inclusive. When Ra2/Ra1 (Ra4/Ra3) is from 3 to 30, bothinclusive, significant turbulence in the first fluid can be generatedwithout decreasing the speed in which the first fluid flows, and thusfurther improve the heat exchange efficiency.

Next, an example of a manufacturing method of the heat exchangeraccording to the embodiment will be described.

First, for the first member, for example, a slurry is manufactured byadding and mixing together a sintering aid, a binder, a solvent, adispersing agent, and the like with a powder formed from primarycomponent raw materials (silicon carbide, alumina, and the like), asappropriate. Then, using this slurry, a ceramic green sheet is formed bya doctor blade method.

Note that examples of other methods for forming the ceramic green sheetinclude manufacturing granules by spray drying and granulating theslurry by a spray drying and granulating method (spray drying method),and molding the obtained granules by roll compaction. Further, theceramic green sheet may also be obtained by a mechanical pressing methodand a cold isostatic pressing (CIP) method using the granules, or bymanufacturing a green body rather than a slurry and using an extrusionmolding method.

Next, the obtained ceramic green sheet is machined into a preferredprofile shape using a metal mold or a laser beam, and machining forforming the introduction hole and the discharge hole is performed. Theslurry is then applied to each ceramic green sheet, the sheets arelaminated and pressurized, and the laminated and pressurized sheets arefired at a firing temperature in accordance with the primary componentraw materials.

Here, to make, in a pair of adjacent introduction holes, a region thatoverlaps with the opening region of the upstream-side introduction hole,exist on the wall that includes the downstream-side introduction holewhen viewed in the direction in which the first fluid flows, thedownstream-side introduction hole may be formed so that the region thatoverlaps with the opening region of the upstream-side introduction holeremains on the ceramic green sheet when viewing the ceramic green sheetfor forming the downstream-side introduction hole overlapped with theceramic green sheet that formed the upstream-side introduction hole.

Specifically, given that the opening shapes are identical, thedownstream-side introduction hole may be provided so as to differ inposition from an outer edge of the ceramic green sheet. Or, thepositions of each hole from the outer edge of the ceramic green sheetmay be made identical and the opening shapes may be made different.Further, to make, in adjacent discharge holes, a region that overlapswith the opening region of the upstream-side discharge hole, exist onthe wall that includes the downstream-side discharge hole when viewed inthe direction in which the first fluid flows, the same method asdescribed above may be used by replacing “introduction hole” with“discharge hole” and thus a description thereof is omitted.

Further, to make at least one of the plurality of first members includea chamfered area on the center section of the at least one of theplurality of the first members, on an edge of the introduction hole ordischarge hole positioned on the downstream side of the first fluid, theedge being on the interior side of the at least one of the plurality ofthe first members, a shape of a blade of a metal mold that comes intocontact with the applicable edge may be tapered or an angle of incidenceof the laser beam may be adjusted during formation of the introductionhole or the discharge hole in the ceramic green sheet described above.Or, after formation of the introduction hole or the discharge hole, apyramid shaped jig may be pressed and pushed against the applicableedge, or the edge may be chamfered by cut processing, for example.

Further, to make at least one of the plurality of first members includea protruding area at a position on the center section of the at leastone of the plurality of the first members, in an area around the edge ofthe introduction hole or discharge hole positioned on the downstreamside of the first fluid, the edge being on the interior side of the atleast one of the plurality of the first members, the protruding area canbe formed in the area around the applicable edge by adjusting theclearance between the used blade of the metal mold and mortar when theintroduction hole or the discharge hole in the ceramic green sheetdescribed above is press-formed by the metal mold. Further, after theintroduction hole or the discharge hole has been provided to the ceramicgreen sheet, a protruding area can be formed by applying a paste havingthe same composition as that used for formation of the ceramic greensheet to the area around the applicable edge. Furthermore, at least oneportion of the applicable edge of the ceramic green sheet may be made toprotrude by pressing the area with a jig or the like.

Next, for the second member, the third member, and the flange portion, aslurry is manufactured by adding and mixing together a sintering aid, abinder, a solvent, a dispersing agent, and the like with a powder formedfrom primary component raw materials (silicon carbide, alumina, and thelike) that constitute each of the members, as appropriate. Then, thesecond member, the third member, and the flange portion can be obtainedby manufacturing granules by spray drying and granulating this slurry bya spray drying and granulating method, manufacturing a powder compacthaving a preferred shape by a mechanical pressing method or a coldisostatic pressing method using the obtained granules, cutting thepowder compact as necessary, and firing. Note that grinding may beperformed as necessary after firing.

Further, the powder compact of which the second member and the thirdmember are made may be obtained by an extrusion molding method using agreen body rather than the slurry. Further, the powder compact of whichthe flange portion is made may be formed by laminating the ceramic greensheets in the same way as with the first member.

Further, to make the arithmetic mean roughness Ra2 of the inner face ofthe introduction hole on the downstream side of the first fluid adjacentto the second member greater than the arithmetic mean roughness Ra1 ofthe inner face of the second member, a method such as follows may beused. For example, the arithmetic mean roughness Ra1 of the inner faceof the second member is measured. Then, to ensure that the arithmeticmean roughness Ra2 of the inner face of the introduction hole on thedownstream side of the first fluid adjacent to the second member isgreater than the arithmetic mean roughness Ra1, the introduction hole isprovided to the ceramic green sheet using an output-adjusted laser beam,the mold is pressed after the introduction hole is provided to theceramic green sheet, or laser processing or blasting may be performedafter firing is performed.

Further, to make the arithmetic mean roughness Ra4 of the discharge holeon the downstream side of the first fluid adjacent to the third membergreater than the arithmetic mean roughness Ra3 of the inner face of thethird member, the same method as described above may be used byreplacing “second member” with “third member” and “introduction hole”with “discharge hole”. Thus, a description thereof is omitted.

Then, the heat exchanger can be obtained by using the obtained firstmember, second member, third member, and flange portion, applying anadhesive to the bonded parts of each member, disposing each member sothat the first fluid communicates therethrough, and curing the adhesiveby thermal treatment. Note that while the above has described shiftingthe positions of the holes to be formed or making the shapes of theholes to be formed different as a way to ensure that, in theintroduction holes adjacent to the second member and the discharge holesadjacent to the third member, regions that overlap with opening regionsof the upstream-side introduction holes (upstream-side discharge holes)exist in the walls including the downstream-side introduction holes(downstream-side discharge holes), when viewed in the direction in whichthe first fluid flows, the hole positions and the hole shapes may bemade identical and the first member adjacent to the second member or thethird member may be bonded in shifted position.

Further, when the number of first members is to be increased in the heatexchanger, the second member and the third member are preferablyprepared and bonded in accordance with the number of first members.

Further, when the number of first members has been increased, the weightof each member of the upper level is applied to the areas around theintroduction hole and the discharge hole of the first member of thelower level, and therefore the second member and the third memberdisposed between the first members may each be disposed so that acentral axis thereof is shifted in the direction in which the firstfluid flows. This makes it possible to decrease the possibility of theoccurrence of flaws and cracks in the areas near the introduction holeand the discharge hole of the first member of the lower level caused bythe applied weight of each member of the upper level.

Note that the preferred adhesive used is an inorganic adhesive superiorin thermal resistance and corrosion resistance. Examples of such aninorganic adhesive include a paste that contains an SiO₂—Al₂O₃—B₂O₃—ROglass (R: alkaline earth metal element) powder and a powder obtained bymixing a silicon metal powder and a silicon carbide powder. When such apaste is used as the inorganic adhesive, the members can be stronglybonded together without deteriorating the members when thermal treatmentis performed, and superior thermal resistance and corrosion resistanceare achieved, and thus, the reliability of the heat exchanger can beimproved.

The present invention has been described in detail above. However, thepresent invention is not limited to the embodiments described above, andvarious modifications or improvements can be made without departing fromthe essential spirit of the present invention.

Further, the heat exchanger described above is not particularly limitedin application as long as heat exchange is performed, allowing suitableuse as a heat exchanger for various laser devices, semiconductorelements, and semiconductor manufacturing devices, for example.

REFERENCE SIGNS LIST

-   1 Heat exchanger-   2 First member-   3 Second member-   4 Third member-   5 Introduction hole-   6 Discharge hole-   7 Introduction channel-   8 First channel-   9 Discharge channel-   10 Second channel-   11 Introduction portion-   12 Discharge portion-   13 Wall including introduction hole and discharge hole-   14 Chamfered portion-   15 Protruding portion-   16 Flange portion

1. A heat exchanger that is formed from a ceramic and performs heatexchange between a first fluid and a second fluid, the heat exchangercomprising: a plurality of first members comprising walls that haveintroduction holes on a first end side and discharge holes on a secondend side, with spaces connecting the introduction holes and thedischarge holes serving as first channels through which the first fluidflows; an introduction channel comprising second members thatcommunicate with the introduction holes at the first end side of theplurality of first members to introduce the first fluid into the firstmembers; and a discharge channel comprising third members thatcommunicate with the discharge holes at the second end side of theplurality of first members to discharge the first fluid that has flowedin the first members; spaces between the plurality of first membersserving as second channels through which the second fluid flows; andwherein, in at least one adjacent pair of the introduction holes, aregion of a wall forming a downstream-side introduction hole of the atleast one adjacent pair overlaps with an opening region of anupstream-side introduction hole of the at least one adjacent pair in adirection in which the first fluid flows.
 2. A heat exchanger that isformed from a ceramic and performs heat exchange between a first fluidand a second fluid, the heat exchanger comprising: a plurality of firstmembers comprising walls that have introduction holes on a first endside and discharge holes on a second end side, with spaces connectingthe introduction holes and the discharge holes serving as first channelsthrough which the first fluid flows; an introduction channel comprisingsecond members that communicate with the introduction holes at the firstend side of the plurality of first members to introduce the first fluidinto the first members; and a discharge channel comprising third membersthat communicate with the discharge holes at the second end side of theplurality of first members to discharge the first fluid that has flowedin the first members; spaces between the plurality of first membersserving as second channels through which the second fluid flows; andwherein, in at least one adjacent pair of the discharge holes, a regionof a wall forming a downstream-side discharge hole of the at least oneadjacent pair overlaps with an opening region of an upstream-sidedischarge hole of the at least one adjacent pair in a direction in whichthe first fluid flows.
 3. The heat exchanger according to claim 1,wherein the at least one of the plurality of first members includes achamfered area in a side of a center section, on an interior edge of thedownstream-side introduction hole, and wherein the center section isbetween the introduction hole and the discharge hole of the at least oneof the plurality of first members.
 4. The heat exchanger according toclaim 1, wherein the at least one of the plurality of first membersincludes a protruding area between the downstream-side introduction holeand an upstream-side discharge hole of the at least one of the pluralityof first members, around an interior edge of the downstream-sideintroduction hole.
 5. The heat exchanger according to claim 1, whereinan arithmetic mean roughness Ra2 of an inner face of each of theintroduction holes adjacent to a downstream side of the second membersis greater than an arithmetic mean roughness Ra1 of an inner face of theone of the second members.
 6. The heat exchanger according to claim 1,wherein an arithmetic mean roughness Ra4 of an inner face of each of thedischarge holes adjacent to a downstream side of the third members isgreater than an arithmetic mean roughness Ra3 of an inner face of theone of the third members.
 7. The heat exchanger according to claim 2,wherein the at least one of the plurality of first members includes achamfered area in a side of a center section, on an interior edge of thedownstream-side discharge hole, and wherein the center section isbetween the introduction hole and the discharge hole of the at least oneof the plurality of the first members.
 8. The heat exchanger accordingto claim 2, wherein the at least one of the plurality of first membersincludes a protruding area on a center section of the at least one ofthe plurality of first members, around an interior edge of thedownstream-side discharge hole, and wherein the center section is thedownstream-side discharge hole and an upstream-side introduction hole.9. The heat exchanger according to claim 2, wherein an arithmetic meanroughness Ra2 of an inner face of each of the introduction holesadjacent to a downstream side of the second members is greater than anarithmetic mean roughness Ra1 of an inner face of the one of the secondmembers.
 10. The heat exchanger according to claim 2, wherein anarithmetic mean roughness Ra4 of an inner face of each of the dischargeholes adjacent to a downstream side of the third members is greater thanan arithmetic mean roughness Ra3 of an inner face of the one of thethird members.